Gearbox mounting

Abstract: A gear box mounting (10) for a motor vehicle has a first member (11) adapted to be mounted with respect to the vehicle gear box (16) and a second member (12) adapted to be connected to a sub-frame (32). The first and second members (11, 12), are interconnected by resilient elements (40, 41) inclined towards one another in a plane transverse to the longitudinal axis of the vehicle in order to provide vertical and lateral compliance of the gear box (16) relative to the sub-frame (32). Buffering means (47, 48, 49) are provided between the first member (11) and the second member (12) and between the first member (11) and the sub-frame (32) to provide continuous and progressive buffering in the vertical upward and downward directions.

Description: The present invention relates to a gearbox mounting for a motor vehicle. FR-A-2155594 and US-A-4151822 disclose resilient mountings which provide compliance in vertical, lateral and longitudinal directions. The mountings also provide for buffering of movement in the upward and downward directions. These designs do not however readily lend themselves to the provision of buffering means to control movement in the lateral and longitudinal directions. The present invention provides a resilient mounting which readily lends itself to the provision of buffering means to control movement in the lateral and longitudinal directions. The resilient mounting of the present invention further utilises surfaces of the sub-frame to which the resilient mounting is secured for buffering purposes, considerably simplifying the design and manufacture of the resilient mounting. According to the present invention a motor vehicle has a gearbox mounted resiliently with respect to the vehicle by means of a gearbox mounting, the gearbox mounting comprising a first member secured to the gearbox, said first member having a vertical axis, and a second member mounted to a sub-frame of the vehicle the second member having a central axis extending normally thereof which is coincident with the vertical axis of the first member, the first and second members being interconnected by a pair of resilient blocks, the resilient blocks being located one on either side of the vertical axis of the first member and being inclined towards one another in a plane transverse to a longitudinal axis of the vehicle in order to provide vertical, lateral and longitudinal compliance of the gearbox relative to the sub-frame, buffering means being provided to provide buffering in the upward and downward directions, characterised in that the second member is secured to the sub-frame on a side thereof remote from the gearbox, the first member extending through an aperture in the sub-frame and being connected to the gearbox, the buffering means being provided between the first member and the remote side of the sub-frame to provide buffering of gearbox movement in the vertical direction away from the sub-frame and the buffering means being provided between the first member and the second member to provide buffering of gearbox movement in a vertical direction towards the sub-frame. Preferably the resilient means are of relatively low spring rate giving low spring rates in the vertical, fore/aft and lateral directions, thereby giving good vibration and noise isolation. The buffering means between the first and second members and between the first member and the sub-frame act to give good control by means of continuous and progressive buffering in the vertical upward and downward directions. According to a preferred embodiment of the invention, further buffering means are provided between the first member and the sub-frame to provide continuous and progressive buffering in the fore/aft direction and/or the direction transverse to the longitudinal axis of the vehicle. The resilient elements and the buffering means are preferably elastomeric elements which are bonded to the first and second members. The first and second members are preferably made from lightweight material, for example aluminium. An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is an isometric view of a gearbox mounting in accordance with the present invention; Figure 2 is a sectional front elevation of the mounting illustrated in Figure 1; Figure 3 is a sectional end elevation of the mounting illustrated in Figure 1; Figure 4 is a plan view of the mounting illustrated in Figure 1, mounted on a sub-frame of a vehicle; and Figure 5 is a side elevation of the mounting illustrated in Figure 1, mounted between a gearbox and a sub-frame of a vehicle. As illustrated in the accompanying drawings, a gearbox mount 10 comprises a first member 11 cast from aluminium and a second member 12 pressed from aluminium. The first member 11 has a central body portion 13 which defines a counterbored aperture 14, through which a bolt 15 may be located to secure the mount 10 to a gearbox 16, as illustrated in Figure 5. The aperture 14 has an enlarged diameter end portion 17 in which locates a correspondingly dimensioned boss 18 on the gearbox 16. The sides of body portion 13 of the first member 11 define a pair of intermediate side faces 20, 21 which are inclined at equal but opposite angles to one another, converging downwardly away from the face of the body portion 13 which is bolted to the gearbox 16. The body portion 13 also defines upper side faces 20a, 21a, front and rear faces 22, 23 which extend vertically. The lower portion 24 of the first member 11 is extended to the front and rear, to provide horizontally extending upper surfaces 25, 26 and a horizontal lower surface 27. The second member 12 has a pair of apertures 30 for bolts 31 by means of which it may be secured to a sub-frame 32 of the vehicle. As illustrated in Figure 4, the second member 12 is mounted with respect to the sub-frame 32, so that it is transverse to the longitudinal axis of the vehicle. The second member 12 defines a pair of faces 35, 36 which are parallel to and aligned normally of the faces 20, 21 of the first member 11 respectively. The faces 35, 36 of the second member 12 are interconnected by a central portion 37. Resilient elastomeric blocks 40, 41 are bonded between faces 20, 35 and 21, 36 respectively, to provide compliant mounting of the first member 11 relative to the second member 12. Elastomeric elements 43, 44, 45, 46, 47, 48 and 49 of generally triangular prismatic shape, are bonded to the faces 20a, 21a, 22, 23, 25, 26 and 27 respectively, the elastomeric element 49 extending into close proximity with a central portion 37 of the second member 12. As illustrated in Figures 4 and 5, the sub-frame 32 is in the form of lattice which is secured to the vehicle. Sub-frame 32 defines a central aperture 50, the second member being secured to the underside of the sub-frame 32 so that the central portion 13 of the first member 11 will extend through the aperture 50 to enable it to be secured to the gearbox 16 as described above. The aperture 50 is defined by front cross-member 51, side members 53, 54 and rear cross-member 52. When the mount 10 is located in position with respect to the sub-frame 32, the elastomeric elements 43 and 44 extend into close proximity to the inner edges of side members 53 and 54 respectively; elastomeric elements 45 and 46 extend into close proximity to the inner edges of cross-members 51 and 52; and elastomeric elements 47 and 48 engage the undersides of cross-members 51, 52. Vertical longitudinal and lateral compliance of the mount 10 is provided by the elastomeric blocks 40, 41, permitting the gearbox 16 to move vertically, transversely or longitudinally relative to the vehicle, thereby isolating vibrations and noise therefrom. Typically, the surfaces 20, 35 and 21, 36 will be inclined at 45° to one another, so that the effective spring rates of the elastomeric blocks 40, 41 in the vertical and lateral directions, will be equal. The angle of inclination of the faces 20, 35 and 21, 36 may however be varied to vary the ratio of the spring rates in the vertical and lateral directions. The elastomeric elements 47, 48 and 49 will provide progressive buffering between the first member 11 and the sub-frame 32 and between the first member 11 and the second member 12, upon upward or downward movement of the gearbox 16, respectively. Elastomeric elements 45 and 46 will provide progressive buffering between the first member 11 and sub-frame 32 for any longitudinal movement of the gearbox in the forward or rearward direction, for example as a result of the loads imposed on the engine and gearbox 16 during braking or slow speed collisions. The elastomeric elements 43 and 44 provide progressive buffering between the first member 11 and sub-frame 32 for any lateral movement, in order to eliminate axle tramp. The elastomeric blocks 40, 41 and elastomeric elements 43, 44, 45, 46, 47, 48 and 49 may be bonded to the respective surfaces of the first and second members 11 and 12, by moulding in contact with said surfaces the elements 43, 44 typically forming an extension of blocks 40, 41. This may be done in a single moulding operation, the first and second members being located in the mould and elastomeric composition being injected into the mould at the appropriate locations. The elastomeric blocks 40, 41 and elastomeric elements 45, 46, 47, 48 and 49 may be made of any suitable natural or synthetic rubber composition, the characteristics of which may be selected to give appropriate spring rates and buffering in the vertical transverse and fore/aft directions. Various modifications may be made without departing from the invention. For example, while the buffering elements disclosed in the above embodiment are of triangular prismatic configuration, prismatic elements and elastomeric blocks of any suitable configuration may be used. Furthermore, while the first and second members are preferably made of lightweight materials, for example aluminium, any suitable material may be used.

Claims: A motor vehicle having a gearbox (16) mounted resiliently with respect to the vehicle by means of a gearbox mounting (10), the gearbox mounting (10) comprising a first member (11) secured to the gearbox (16), said first member (11) having a vertical axis, and a second member (12) mounted to a sub-frame (32) of the vehicle the sub-frame (32) being disposed beneath the gearbox, the second member (12) having a central axis extending normally thereof which is coincident with the vertical axis of the first member (11), the first and second members (11, 12) being interconnected by a pair of resilient elements (40, 41), the resilient elements (40, 41) being located one on either side of the vertical axis of the first member (11) and being inclined towards one another in a plane transverse to a longitudinal axis of the vehicle in order to provide vertical, lateral and longitudinal compliance of the gearbox (16) relative to the sub-frame (32), buffering means (47, 48, 49) being provided to provide buffering in the upward and downward directions, characterised in that the second member (12) is secured to the sub-frame (32) on the underside thereof, the first member (11) extending through an aperture (50) in the sub-frame (32) and being connected to the gearbox (16), said buffering means (47, 48, 49) being provided between the first member (11) and the underside of the sub-frame (32) to provide buffering of gearbox movement in an upward direction and between the first member (11) and the second member (12) to provide buffering of gearbox movement in a downard direction. A vehicle according to claim 1 characterised in that further buffering means (43, 44) are provided between the first member (11) and the sub-frame (32) to provide buffering transverse to the longitudinal axis of the vehicle. A vehicle according to Claims 1 or 2 characterised in that further buffering means (45, 46) are provided between the first member (11) and the sub-frame (32) to provide buffering in the longitudinal direction of the vehicle. A vehicle according to any one of the preceding claims characterised in that the first member (11) has a pair of side faces (20, 21) inclined at equal but opposite angles with respect to one another, the second member (12) having a pair of inclined faces (35, 36), each inclined face (35, 36) on the second member (12) being parallel to and disposed normally of one of the inclined faces (20, 21) on the first member (11), elastomeric blocks (40, 41) being bonded between the inclined faces (20, 21) on the first member (11) and the opposed inclined faces (35, 36) on the second member (12). A vehicle according to any one of the preceding claims characterised in that the buffering means (43, 44, 45, 46, 47, 48, 49) are elastomeric elements which are bonded to the first member (11). A vehicle according to Claim 5 characterised in that the elastomeric elements (43, 44, 45, 46, 47, 48, 49) are of triangular prismatic configuration. A vehicle according to Claim 5 or 6 characterised in that the first member (11) has vertically extending front and rear faces (22, 23), elastomeric elements (45, 46) being bonded to these faces (22, 23) to provide the buffering means for engagement of members (51, 52) of the sub-frame (32) defining the aperture (50), for buffering in the longitudinal direction of the vehicle. A vehicle according to Claim 5 or 6 characterised in that the first member (11) has vertically extending side faces (20a, 21a), elastomeric elements (43, 44) being bonded to these faces (20a, 21a) to provide the buffering means for engagement of members (53, 54) of the sub-frame (32) defining the aperture (50), for buffering in the direction transverse to the longitudinal axis of the vehicle. A vehicle according to any one of Claims 5 to 8 characterised in that the first member (11) has a lower portion (24) which defines a pair of horizontal upper surfaces (25, 26) extending to the front and rear and a horizontal lower surface (27), elastomeric elements (47, 48, 49) being bonded to the horizontal upper and lower surfaces (25, 26, 27) to provide the buffering means between the first member (11) and the sub-frame (32) and between the first member (11) and the second member (12) to provide buffering in the vertical direction. A vehicle according to any one of the preceding claims characterised in that the first member (11) defines a central aperture (14) for location of fixing means (15) by which it may be secured to the gearbox (16) of the vehicle.

Inventors: BURKE SEAN ANDREW, PREECE GARRY JAMES, BURKE, SEAN ANDREW, PREECE, GARRY JAMES
Applicants: JAGUAR CARS, JAGUAR CARS LIMITED
Application year: 1994
Main classification: F16H57
IPC codes: B60K17, F16H57, B60K5, F16F1, F16F15